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Discussion Starter #1
I replaced the CHTS and harness this weekend on my car and I am still having a rough starting problem when cold. What would be the next thing to try to replace?

Thanks,

Jason
1986na 5 speed.
 

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Discussion Starter #3
It's easy to start up right away in the mornings but I have to put my foot on the gas peddle for about 2 minutes at about 1K RPM's until it gets warm enough to idle normal. If I don't do anything, it idles irradicaly and cuts out. I still detect a gassy smell in the morning after I start it up and when I accelerate into gears (the first minute or two of driving i hear a quick hissing noise). I hear some type of a whining/motor sound when it's warming up (like the fuel pump.) But once the car is warm, and driven for a minute or two it drives great.
 

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The "whining/motor" noise is your fuel pump and that particular item is not unusual or a concern.

I would run your ECU codes (follow procedure in the Haynes manual) now that you have installed your new CHTS and subharness. It will flag if it isn't on tight enough or something else has happened during installation that is causing it to fail.

Outside of that, I leave it to the guru's!
 

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Probably your AAC valve. Its right in front of your EGR valve on the passenger side of the plenum. Try removing it and cleaning it out. or find one from a junkyard car and put it on. I bet that will solve it.
 

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Discussion Starter #6
What does the AAC valve stand for and would it be cost effective to replace it with a new one?

What about the O2 sensor? Should I try to replace this too?

Maybe I should try to invest in a Haynes manual.

Can the codes/procedures for doing this be found online?
 

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Buy the manual, no question. You could find them somewhere online but having the Haynes manual is important for the amatuer home mechanic. It's only $15 and it will pay for itself after the first use.

Run the codes, then go from there. The codes will flag several different sensors including the 02 sensor.

Good luck!
 

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phxZ31 has this one right; we had this debate a few months back and it sounds like the AAC (Auxillary Air Control) is definately your problem. I experienced the exact same symptoms you are, and when mine was replaced with a brand new AAC it started up perfect. So perfect infact I think it had been shot the entire time i've had the car because it started up like a beast just by turning the ignition and it never had done that before without pressing the gas at least a little bit.

Get it replaced asap, if it's anything like mine was and idling real rough first thing in the morning when it's cold as sh!t, that's very bad. Be nice to your Z and dont let it knock or idle too low ever, especially when it's cold. I personally got a brand new AAC to save any dramas, it's a cheap part and I couldn't be bothered cleaning it up.
 

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The "AAC" is fitted to the LHS of turbo plenums and uses an electrical signal from the ECU (of approx 160Hz with varying duty cycle) to control idle speed.

Both NA and turbo engines have an "Air Regulator" fitted to the RHS of the plenum. The AR contains a bimetal-controlled rotary shutter that adds metered air when the engine is cold to raise idle speed.

Despite the simplicity of the AR, it is not a particularly reliable part in the long term. It is uncommon to find one that still operates correctly after 20 years.

FSMs can be found online at carfiche.com.
 

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Yeah it's confusing, I believe the Air Regulator as you mentioned is referred to as the Auxilary Air Valve here in AU hence the confusion with the Auxillary Air Control. phxZ31 and I had this confusing discussion a few months back. Thanks for clearing that up tho Mister_T, you certainly know your stuff!
 

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Sticking to Nissan terminology here helps us all.
However, the same part may have different names in the FSMs and parts fiche. As long as we know the Nissan part name and maybe where the name came from (FSM vs fiche) it makes things a lot simpler.

Aftermarket part suppliers can have their own terminology. The Air Regulator can be called many things, such as "cold start air valve" or other variations of that theme. If you know the name of the part and its function there is a fair chance you can get the correct part.

I recently bought an Air Regulator from Petroject AU. They didn't call it an Air Regulator but the parts interpreter guy was able figure out what I wanted.
Curiously, the supplied air reg had a Nissan-JECS OEM label on it but the air reg came in a Bosch box, and at a substancial saving over the Nissan dealer price I might add.

Knowing stuff is easy when the FSMs are consulted. If eveyone in this forum (and indeed most car forums) actually read the FSMs then 80% of questions in this forum might not occur.
I'll never remember the entire contents of an FSM, but I know where to look something up when I need it.
 

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Mister T is Absolutly CORRECT .......... and a valuable asset to the Forum!!!

THE AIR REGULATOR (AR) is Located on the Passenger Side of the Engine.


The AAC AUXILLIARY AIR CONTROL (AAC) is located on the Driver's side of the Engine.

Some of the other Veterans, slipped in their Post..
 
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